Act as the wisest have acted before you, and do not commence your exercises in philosophy in those regions where an error can deliver you over to the executioner.

Georg C. Lichtenberg (1742-1799) German physicist, writer

Aphorisms, Notebook C, #16 [142] (1772-73) [tr. Hollingdale (1960)]
    (Source)

Alternate translation: "Act as the wisest before you have acted, and do not begin your philosophical exercises where an error can deliver you into the hands of the executioner." [tr. Tester (2012)]